On 09/06/2013 04:49 AM, Alex Williamson wrote:
> On Fri, 2013-08-30 at 20:15 +1000, Alexey Kardashevskiy wrote:
>> From: David Gibson <da...@gibson.dropbear.id.au>
>>
>> This patch uses the new IOMMU notifiers to allow VFIO pass through devices
>> to work with guest side IOMMUs, as long as the host-side VFIO iommu has
>> sufficient capability and granularity to match the guest side. This works
>> by tracking all map and unmap operations on the guest IOMMU using the
>> notifiers, and mirroring them into VFIO.
>>
>> There are a number of FIXMEs, and the scheme involves rather more notifier
>> structures than I'd like, but it should make for a reasonable proof of
>> concept.
>>
>> Signed-off-by: David Gibson <da...@gibson.dropbear.id.au>
>> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
>>
>> ---
>> Changes:
>> v4:
>> * fixed list objects naming
>> * vfio_listener_region_add() reworked to call memory_region_ref() from one
>> place only, it is also easier to review the changes
>> * fixes boundary check not to fail on sections == 2^64 bytes,
>> the "vfio: Fix debug output for int128 values" patch is required;
>> this obsoletes the "[PATCH v3 0/3] vfio: fixes for better support
>> for 128 bit memory section sizes" patch proposal
>> ---
>> hw/misc/vfio.c | 137
>> +++++++++++++++++++++++++++++++++++++++++++++++++++++----
>> 1 file changed, 128 insertions(+), 9 deletions(-)
>>
>> diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
>> index c16f41b..53791fb 100644
>> --- a/hw/misc/vfio.c
>> +++ b/hw/misc/vfio.c
>> @@ -150,10 +150,18 @@ typedef struct VFIOContainer {
>> };
>> void (*release)(struct VFIOContainer *);
>> } iommu_data;
>> + QLIST_HEAD(, VFIOGuestIOMMU) giommu_list;
>> QLIST_HEAD(, VFIOGroup) group_list;
>> QLIST_ENTRY(VFIOContainer) next;
>> } VFIOContainer;
>>
>> +typedef struct VFIOGuestIOMMU {
>> + VFIOContainer *container;
>> + MemoryRegion *iommu;
>> + Notifier n;
>> + QLIST_ENTRY(VFIOGuestIOMMU) giommu_next;
>> +} VFIOGuestIOMMU;
>> +
>> /* Cache of MSI-X setup plus extra mmap and memory region for split BAR map
>> */
>> typedef struct VFIOMSIXInfo {
>> uint8_t table_bar;
>> @@ -1917,7 +1925,63 @@ static int vfio_dma_map(VFIOContainer *container,
>> hwaddr iova,
>>
>> static bool vfio_listener_skipped_section(MemoryRegionSection *section)
>> {
>> - return !memory_region_is_ram(section->mr);
>> + return !memory_region_is_ram(section->mr) &&
>> + !memory_region_is_iommu(section->mr);
>> +}
>> +
>> +static void vfio_iommu_map_notify(Notifier *n, void *data)
>> +{
>> + VFIOGuestIOMMU *giommu = container_of(n, VFIOGuestIOMMU, n);
>> + VFIOContainer *container = giommu->container;
>> + IOMMUTLBEntry *iotlb = data;
>> + MemoryRegion *mr;
>> + hwaddr xlat;
>> + hwaddr len = iotlb->addr_mask + 1;
>> + void *vaddr;
>> + int ret;
>> +
>> + DPRINTF("iommu map @ %"HWADDR_PRIx" - %"HWADDR_PRIx"\n",
>> + iotlb->iova, iotlb->iova + iotlb->addr_mask);
>> +
>> + /*
>> + * The IOMMU TLB entry we have just covers translation through
>> + * this IOMMU to its immediate target. We need to translate
>> + * it the rest of the way through to memory.
>> + */
>> + mr = address_space_translate(&address_space_memory,
>> + iotlb->translated_addr,
>> + &xlat, &len, iotlb->perm & IOMMU_WO);
>> + if (!memory_region_is_ram(mr)) {
>> + DPRINTF("iommu map to non memory area %"HWADDR_PRIx"\n",
>> + xlat);
>> + return;
>> + }
>> + if (len & iotlb->addr_mask) {
>> + DPRINTF("iommu has granularity incompatible with target AS\n");
>> + return;
>> + }
>> +
>> + vaddr = memory_region_get_ram_ptr(mr) + xlat;
>> +
>> + if (iotlb->perm != IOMMU_NONE) {
>> + ret = vfio_dma_map(container, iotlb->iova,
>> + iotlb->addr_mask + 1, vaddr,
>> + !(iotlb->perm & IOMMU_WO) || mr->readonly);
>> + if (ret) {
>> + error_report("vfio_dma_map(%p, 0x%"HWADDR_PRIx", "
>> + "0x%"HWADDR_PRIx", %p) = %d (%m)",
>> + container, iotlb->iova,
>> + iotlb->addr_mask + 1, vaddr, ret);
>> + }
>> + } else {
>> + ret = vfio_dma_unmap(container, iotlb->iova, iotlb->addr_mask + 1);
>> + if (ret) {
>> + error_report("vfio_dma_unmap(%p, 0x%"HWADDR_PRIx", "
>> + "0x%"HWADDR_PRIx") = %d (%m)",
>> + container, iotlb->iova,
>> + iotlb->addr_mask + 1, ret);
>> + }
>> + }
>> }
>>
>> static void vfio_listener_region_add(MemoryListener *listener,
>> @@ -1926,11 +1990,10 @@ static void vfio_listener_region_add(MemoryListener
>> *listener,
>> VFIOContainer *container = container_of(listener, VFIOContainer,
>> iommu_data.listener);
>> hwaddr iova, end;
>> + Int128 llend;
>> void *vaddr;
>> int ret;
>>
>> - assert(!memory_region_is_iommu(section->mr));
>> -
>> if (vfio_listener_skipped_section(section)) {
>> DPRINTF("SKIPPING region_add %"HWADDR_PRIx" - %"PRIx64"\n",
>> section->offset_within_address_space,
>> @@ -1946,21 +2009,57 @@ static void vfio_listener_region_add(MemoryListener
>> *listener,
>> }
>>
>> iova = TARGET_PAGE_ALIGN(section->offset_within_address_space);
>> + llend = int128_make64(section->offset_within_address_space);
>> + llend = int128_add(llend, section->size);
>> + llend = int128_and(llend, int128_exts64(TARGET_PAGE_MASK));
>
> So you're still looking for me to pickup patches 1/3 & 2/3 from the
> previous int128 series for this?
Oops. Just noticed the question.
Yes, please. Your tree is a lot faster :)
>> +
>> + if (int128_ge(int128_make64(iova), llend)) {
>> + return;
>> + }
>> +
>> + memory_region_ref(section->mr);
>> +
>> + if (memory_region_is_iommu(section->mr)) {
>> + VFIOGuestIOMMU *giommu;
>> +
>> + DPRINTF("region_add [iommu] %"HWADDR_PRIx" - %"HWADDR_PRIx"\n",
>> + iova, int128_get64(int128_sub(llend, int128_one())));
>> + /*
>> + * FIXME: We should do some checking to see if the
>> + * capabilities of the host VFIO IOMMU are adequate to model
>> + * the guest IOMMU
>> + *
>> + * FIXME: This assumes that the guest IOMMU is empty of
>> + * mappings at this point - we should either enforce this, or
>> + * loop through existing mappings to map them into VFIO.
>
> I would hope that when you do the below
> memory_region_register_iommu_notifier() the callback gets a replay of
> the current state of the iommu like we do for a memory region when we
> register the listener that gets us here. Is that not the case?
>From what I see, it just adds a notifier:
void memory_region_register_iommu_notifier(MemoryRegion *mr, Notifier *n)
{
notifier_list_add(&mr->iommu_notify, n);
}
>> + *
>> + * FIXME: For VFIO iommu types which have KVM acceleration to
>> + * avoid bouncing all map/unmaps through qemu this way, this
>> + * would be the right place to wire that up (tell the KVM
>> + * device emulation the VFIO iommu handles to use).
>> + */
>> + giommu = g_malloc0(sizeof(*giommu));
>> + giommu->iommu = section->mr;
>> + giommu->container = container;
>> + giommu->n.notify = vfio_iommu_map_notify;
>> + QLIST_INSERT_HEAD(&container->giommu_list, giommu, giommu_next);
>> + memory_region_register_iommu_notifier(giommu->iommu, &giommu->n);
>> +
>> + return;
>> + }
>> +
>> + /* Here we assume that memory_region_is_ram(section->mr)==true */
>> +
>> end = (section->offset_within_address_space +
>> int128_get64(section->size)) &
>> TARGET_PAGE_MASK;
>
> Why isn't this now calculated from llend?
I did not want to change the existing code :) I will fix it.
.
> I thought that was part of
> why the int128 stuff was rolled in here.
Not sure that I understood the note. Everything I wanted here was not
calling int128_get64() for IOMMU case.
--
Alexey
